As a third generation semiconductor materials typical of wide band gap semiconductor, gallium nitride (GaN) have many properties superior to silicon (Si) materials. GaN is an excellent high frequency, high voltage, high temperature and high power semiconductor material with broad prospective applications in civil and military areas. With advances in GaN technology, in particularly the coming maturity of the large diameter GaN epitaxial growth technology, the commercialization of GaN power semiconductor is expected to be the choice technology solution for high performance low power applications. The GaN power devices have thus attracted the attentions of world leading semiconductor manufacturers and research institutes.
Different from traditional MOSFET, junctionless transistors are formed by source region, channel, drain region, gate oxide layer and gate electrode. The impurity doping type is the same from the source region, channel to the drain region with no PN junction formed. It is a majority carrier conduction type device. The gate bias voltages can modulate the majority carriers in the channel to be either accumulation or depletion which in turn reflects the change of channel conductance and channel current. When the gate bias voltage increases to a level such that the channel near the drain region is depleted of majority carriers, the channel becomes a quasi-infinite resistor and the device is turned off. As the majority carriers are immune to lattice imperfection in the interface between the gate oxide and the semiconductor channel, the interface scattering effects on carriers are also limited. This can result in improved carrier mobility. In addition, because the junctionless transistor is a majority carrier conduction device with high response speed, and the electric field strength along the channel direction near the drain is much lower than the conventional reverse-channel MOS transistor, Therefore, the device's performance and reliability are greatly enhanced.